| 摘要 |
<p>Compounds of general formula (I), salts and metabolically labile esters thereof; wherein R1 represents hydrogen or a hydroxyl protecting group; R2 represents hydrogen or a carboxyl protecting group; R3 represents hydrogen or a nitrogen protecting group; Z represents a methylene group optionally substituted by methyl; X represents a bond or a C1-2alkylene chain or an ethenylene chain; A represents a C2-4alkylene chain or A is a chain of 2 to 4 members one of which is an oxygen or sulphur atom or the group NH or a substituted derivative thereof and the other members are methylene groups; and R4 represents an optionally substituted phenyl group, a process for their preparation and their use as antibacterial agents.</p> |
